introducing connection timeout and query read timeout

[jaroslawk]

Alaisi,

We are using your driver in our app under AWS cloud and we are missing some failover scenarios support:

• connection timeout - max wait time for connecting to the DB. Without it we wait forever for the response from DB and there is no way for us to signal error to RX side.
• read timeout - this is similar situation. On the network issues one need to be prepare to have no feedback packet when attempting to use existing connection.

I have provided you the tests for those scenarios.

Please let me know what do you think about those changes?

[jaroslawk]

@alaisi I am removing not important changes and also I see timeout was not working correctly. This time it covers also initial message - this covers our usage.

Let me know what you think.

I will add utest to prove it works as expected.

[jaroslawk]

@jaceksokol - good point. I have updated the code to take only connections which are alive under consideration.